Change opacity at a layer marker

Hi guys

I am trying to recreate in 6.5, the opacity flash aexpression found in version 7s presets. Im having difficulty with it, and although the script does not throw up any errors, it still won't change the opacity at my markers.

I have applied the espression slider to a layer and also the solid composite effect. To this i have applied the expression

try{
flashWidth = effect("Opacity Flash - layer markers")("Flash Width (msec)") / 2000;
timeToMarker = Math.abs(time - marker.nearestKey(time).time);
easeOut(timeToMarker, flashWidth, 0, 100, 0)
}catch(err1){
100
}

And i have also adjusted the effect parameters so that it is on Add mode.

No luck... and ideas as to why.

Thanks alot
Chris